also bush-whacker, 1809, American English, literally "one who beats the bushes" (to make his way through), perhaps modeled on Dutch bosch-wachter "forest keeper;" see bush (n.) + whack (v.). In American Civil War, "irregular who took to the woods" (1862), variously regarded as patriot guerillas or as freebooters. Hence bushwhack (v.), 1837; bushwhacking (1826).